1. Field
The present invention relates to processing weapon fire information such as gunfire, and, more particularly, to systems, methods, devices and computer-readable media associated with weapon fire location augmented by echo/reflection processing.
2. Description of Related Information
Measuring the locations of acoustic sources over an extensive area requires an array of sensors. One example of an outdoor array is an urban gunshot location system. An exemplary example of such a system is given in U.S. Pat. No. 5,973,998 “Automatic Real-Time Gunshot Locator and Display System,” which describes the ShotSpotter® system.
In an urban setting, buildings cause refraction, reflection, and blockage of audio waves propagating from gunfire to the various sensors. Reflections (multipath) are usually not important to triangulation or multilateration if the direct path is also received, as subsequent impulses can be discarded. In traditional location systems these reflection hitherto fore have been ignored.
An attempt to mitigate blockage and bad effects from reflection is taught in U.S. Pat. No. 7,474,589 titled “Acoustic Location of Gunshots Using Combined Angle of Arrival and Time of Arrival Measurements,” which is incorporated herein by reference in entirety and integrated with this application. Azimuthal sensors allow a fewer number of sensors to locate and confirm a location, and they can lift mathematical ambiguities for solutions where two distinct roots (location solutions) using arrival times only are present.
The use therein of “pseudo-sensors” to ease location computation is also contemplated in the present invention. Briefly, a pseudo-sensor is a useful computational algorithm that converts a location problem using input data consisting of a mixed set of times of arrival (ToA) and angles of arrival (AoA) into a set of only ToA values, allowing, e.g., use of multilateration computation methods Innovations consistent with concepts involving virtual sensor(s) using echoes are disclosed in this patent.